Digital Update, 8th Edition by Sharon Stranford; Judy
Owen; Jenni Punt; Patricia Jones
Complete Chapters 1-21| Verified Q&As for Exam
Preparation| All Figures Included| A+ PASS GUARANTEED
Chapter 01
1. Two of the main, early theories proposed to explain how antigen - specific antibodies develop
were the instructional theory and the selective theory. How did the two differ? Which was
ultimately shown to be
CORRECT?
,CORRECT ANSWER : The selective theory says that, when an antigen receptor binds with an
antigen, the cell becomes activated (or the cell is selected to proliferate and secrete more
copies of the receptor). The instructional theory says that the antigen receptor molds its elf to
the antigen. The selective theory was shown to be correct.
2. Often, serendipity plays a role in significant scientific discoveries. In your own words, explain
how serendipity led Pasteur to discover a cholera vaccine.
CORRECT ANSWER : Pasteur developed the vaccine in chickens, which were in short supply. He
challenged groups of chickens with cholera bacteria —some of which were previously exposed to
an attenuated version of cholera bacteria. Only the previously exposed animals were pro tected
from a new challenge, which led to the use of weakened pathogens as vaccines.
3. Despite its having been eradicated on a global scale, smallpox is presently considered a
potential bioterrorism threat. Why? Use evidence to support your answer.
CORRECT ANSWER : After eradication was achieved, smallpox vaccination programs largely
ended. As populations continued to grow over time, an ever - increasing percentage of the human
population remains unvaccinated and thus, is still susceptible to the disease.
4. Prior to 1999, it was claimed that a thimerosal additive in vaccines was contributing to the rising
incidence of autism. If the claims were true, what resultant trend might you expect to observe
in the rate of autism once thimerosal was removed from vaccines?
CORRECT ANSWER : One would reasonably expect a decrease in the rate of autism. However,
cases of autism continued to rise after thimerosal was removed from vaccines in 2001.
5. Given the discovery and development of effective antibiotics, make an argument for the
continued use of vaccines against bacterial pathogens. Use evidence to support your ans wer.
CORRECT ANSWER : Antibiotics are used for treatment of disease, not typically for prevention.
Antibiotic treatment is not foolproof (considering the rising incidence of antibiotic resistance).
Vaccines are a preventative measure, and prevention is the gold standard for i nfectious disease
control measures.
6. You have a friend unfamiliar with immunology, and he asks you the following question: "Why do I
need the flu shot every year, but don't need an annual chickenpox vaccine?" As a student of
immunology, how would you explain this discrepancy to your friend? U se evidence to support
your ans wer.
CORRECT ANSWER : The virus that causes the flu changes every year - as a result, a new flu
vaccine must be prepared each year based on a predication of the most common forms of the
virus likely to be encountered. Vaccines are specific in the type of pathogen against whic h they
,protect, and protection against one type does not guarantee protection against pathogens that
are closely - related.
7. Provide one benefit and one drawback of generating random recognition receptors during the
development of B cells.
CORRECT ANSWER : A benefit is having the capacity to recognize and respond to diverse
pathogens as they evolve. A drawback is that some recognition receptors could potentially
recognize and target host
antigens.
8. A portion of our immune systems' white blood cells is constantly circulating throughout the
body via circulation and lymphatics. What is the benefit of such circulation?
CORRECT ANSWER : The circulation of the white blood cells allows for a more comprehensive
surveillance of the body for the presence of potential pathogens. A significant portion of the
human body is constantly exposed to potential microbial pathogens.
9. Complete the following table by comparing and contrasting innate and adaptive immune
responses.
Innate Immunity Adaptive Immunity
Is mediated by what cells?
What do they recognize?
How are the receptors encoded?
Why can't they control all infections alone?
What do they do in response to antigen?
CORRECT ANSWER :
Adaptive
Innate Immunity Immunity
Macrophages, NK
Is mediated by T cells and B
cells, neutrophils,
what cells? cells
mast cells eosinophils
What do they Specific
, Pathogen patterns
recognize? epitopes
How are the Rearranged
receptors Germ line gene segments
encoded?
Why can't they
Pathogens evolve Takes
too long control all
escape mechanisms to develop
infections alone?
What do they do Produce
Engulf and destroy, in response
to antibodies, kill
induce inflammation
antigen? infected cells
10. What are the hallmarks of inflammation? Describe the physical characteristics of someone
experiencing an inflammatory response.
CORRECT ANSWER : Redness, swelling, heat, pain. Someone experiencing inflammation
might have localized swelling and redness or itching or may be experiencing faintness due
to a lowering of blood pressure if more severe.
11. Upon receiving immune serum as a treatment for a venomous snake bite, would the recipient
be immune from future bites of the same species?
CORRECT ANSWER : In the short - term, probably, as the serum contains protective antibodies
against the venom. In the long - term, no, as serum treatment is a form of passive immunity.
Passive immunity does not generate long - lived memory cells.
12. Provide one common feature of and two differences between B - cell receptors and PRRs.
CORRECT ANSWER : A common feature is that they both are used to recognize foreign antigens.
A B - cell receptor is more selective than a PRR. The DNA that encodes for a PRR in an individual
is inherited.
The DNA that encodes for a mature B - cell receptor from an individual is not passed on to
offspring.